From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36820) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4OBM-00021r-Kh for qemu-devel@nongnu.org; Thu, 03 Dec 2015 02:20:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a4OBJ-0007R4-ET for qemu-devel@nongnu.org; Thu, 03 Dec 2015 02:20:00 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:13322) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4OBI-0007Qs-Ir for qemu-devel@nongnu.org; Thu, 03 Dec 2015 02:19:57 -0500 References: <1448357149-17572-1-git-send-email-zhang.zhanghailiang@huawei.com> <1448357149-17572-15-git-send-email-zhang.zhanghailiang@huawei.com> <20151201181905.GC31209@work-vm> From: Hailiang Zhang Message-ID: <565FED03.3060108@huawei.com> Date: Thu, 3 Dec 2015 15:19:31 +0800 MIME-Version: 1.0 In-Reply-To: <20151201181905.GC31209@work-vm> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH COLO-Frame v11 14/39] ram: Split host_from_stream_offset() into two helper functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: lizhijian@cn.fujitsu.com, quintela@redhat.com, yunhong.jiang@intel.com, eddie.dong@intel.com, peter.huangpeng@huawei.com, qemu-devel@nongnu.org, arei.gonglei@huawei.com, stefanha@redhat.com, amit.shah@redhat.com, hongyang.yang@easystack.cn On 2015/12/2 2:19, Dr. David Alan Gilbert wrote: > * zhanghailiang (zhang.zhanghailiang@huawei.com) wrote: >> Split host_from_stream_offset() into two parts: >> One is to get ram block, which the block idstr may be get from migration >> stream, the other is to get hva (host) address from block and the offset. >> >> Signed-off-by: zhanghailiang > > OK, I see why you're doing this from the next patch. > >> --- >> v11: >> - New patch >> --- >> migration/ram.c | 29 +++++++++++++++++++++-------- >> 1 file changed, 21 insertions(+), 8 deletions(-) >> >> diff --git a/migration/ram.c b/migration/ram.c >> index cfe78aa..a161620 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -2136,9 +2136,9 @@ static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host) >> * offset: Offset within the block >> * flags: Page flags (mostly to see if it's a continuation of previous block) >> */ >> -static inline void *host_from_stream_offset(QEMUFile *f, >> - ram_addr_t offset, >> - int flags) >> +static inline RAMBlock *ram_block_from_stream(QEMUFile *f, >> + ram_addr_t offset, >> + int flags) >> { >> static RAMBlock *block = NULL; >> char id[256]; >> @@ -2150,22 +2150,31 @@ static inline void *host_from_stream_offset(QEMUFile *f, >> return NULL; >> } >> >> - return block->host + offset; >> + return block; >> } >> - >> len = qemu_get_byte(f); >> qemu_get_buffer(f, (uint8_t *)id, len); >> id[len] = 0; >> >> block = qemu_ram_block_by_name(id); >> if (block && block->max_length > offset) { >> - return block->host + offset; >> + return block; >> } >> >> error_report("Can't find block %s", id); >> return NULL; >> } >> >> +static inline void *host_from_ram_block_offset(RAMBlock *block, >> + ram_addr_t offset) >> +{ >> + if (!block) { >> + return NULL; >> + } >> + >> + return block->host + offset; >> +} > > That's almost the same as ramblock_ptr in include/exec/ram_addr.h, but > it assert's rather than doing NULL on errors. > Hmm, i didn't notice that before. > I'm not sure about this, but can I suggest: > > ram_block_from_stream(QEMUFile *f, int flags) > > doesn't have the offset; just finds the block and handles the CONT. > > bool offset_in_ramblock(RAMBlock *b, ram_addr_t offset); > > actually does the check; put this in exec.c, and declare it in include/exec/ram_addr.h > > void *ramblock_ptr_try(RAMBlock *block, ram_addr_t offset) > which returns NULL if offset_in_ramblock fails, and otherwise returns the result > of ramblock_ptr - again put that in include/exec/ram_addr.h > That sounds good. I will add the ramblock_ptr_try() and keep the ramblock_ptr(). They have different behavior when the check failed. I'm not supposed to break it. > (I'm not sure about this - I almost suggested changing ramblock_ptr to not do > the checks, and just add a call to assert(offset_in_ramblock) before each use, but > that sounded too painful). > Yes, that's not so good. > Hmm - we check here for block->max_length > offset - where as the check in > ram_addr.h is used_length - I wonder if we should be using used_length? > Er, i think we should use used_length instead of max_length. Thanks, zhanghailiang > Dave > >> + >> /* >> * If a page (or a whole RDMA chunk) has been >> * determined to be zero, then zap it. >> @@ -2310,7 +2319,9 @@ static int ram_load_postcopy(QEMUFile *f) >> trace_ram_load_postcopy_loop((uint64_t)addr, flags); >> place_needed = false; >> if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE)) { >> - host = host_from_stream_offset(f, addr, flags); >> + RAMBlock *block = ram_block_from_stream(f, addr, flags); >> + >> + host = host_from_ram_block_offset(block, addr); >> if (!host) { >> error_report("Illegal RAM offset " RAM_ADDR_FMT, addr); >> ret = -EINVAL; >> @@ -2441,7 +2452,9 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) >> >> if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE | >> RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) { >> - host = host_from_stream_offset(f, addr, flags); >> + RAMBlock *block = ram_block_from_stream(f, addr, flags); >> + >> + host = host_from_ram_block_offset(block, addr); >> if (!host) { >> error_report("Illegal RAM offset " RAM_ADDR_FMT, addr); >> ret = -EINVAL; >> -- >> 1.8.3.1 >> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > . >